Researchers at the Incheon National University in South Korea studied how the health-threatening additives in plastic wastes diffuse in the environment. When found in bodies of water, it became important for the SoKor university researchers to develop a more accurate method of measuring the rate by which plastic additives diffuse.
Plastic wastes are filled with additives in order to make processing effortless and more cost-efficient. However, while plastic materials are non biodegradable, the additives in plastic wastes that stayed in a particular environment for a long time tend to ooze.
According to the recent research, the additives in plastics diffuse in different rates, which made it necessary for the university scientists to develop a new method of evaluating the contamination and exposure risks presented by plastic additives like styrene oligomers (SOs).
Why is Styrene Oligomer Harmful
Styrene oligomer (SO) is a type of plastic additive that has been medically proven as causing thyroid problems and hormonal dysfunction. However, SoKor health authorities are relying on scientists to come up with recommendations for the right environmental actions to take. Yet modern scientists have been having difficulties in accurately measuring proportions of bioavailable fraction, or the leachable amount of plastic additives as they occur in different environments.
It is usual for the leached SO compounds to stay contained in the plastic waste material for quite some time before they diffuse, to which the rates by which SO diffusions vary.
The Study of Plastic Additives Led to a New Study Method
As their assessment of the plastic additives produced inaccurate results, Professor Seung-Kyu Kim and his team of Incheon National University researchers developed a different method.
What they did was to collect surface sediments in an artificial lake linked to the Yellow Sea, a suspected source of SO contamination due to being surrounded by marine buoys and land area. According to Professor Kim, their goal was to identify the main source of the contaminants and measure the extractable amount from the established source. The team evaluated one of the potential sources by dissecting a local polystyrene buoy, whilst measuring the leached additives content and the related level of SO concentration.
The main finding formed by their research is that there is a difference between the dilution rate of SO dimers (SDs) and trimers (STs), which proved that the composition in buoys and coastal sediments vary. The trimers had heavy, hydrophobic molecules, which made them stick and move at a slower rate while in the potential source.
On the other hand, SO dimers had lighter molecules that leach out effortlessly and reach farther distances. Based on the comparative differences, the research team concluded that the farther the source of the SD contamination, the greater the SD to ST ratio.
The ratio was then used as reference in identifying the source of the styrene oligomers and in estimating the leachable plastic additives in the source. Professor Kim said the method they developed is important in evaluating human and ecological threats produced by the plastic additives. Furthermore, it also makes risk assessments of potential exposure more accurate, which in turn, will help create policies that prohibit hazardous and leachable additives.